若尔盖湿地和草地退化过程中土壤理化性质的变异

Variation of Soil physical and Chemical Properties in the Degradation Process of Wetland and Grassland in Zoigê

通过对若尔盖湿地和草地的退化沙化调查及采样分析,结果表明:在若尔盖湿地和草地退化沙化演变过程中,土壤的有机质含量、养分元素N、P的全量和有效性N、P、K含量呈明显的下降趋势;土壤粘粒、粉砂粒含量不断降低,沙粒含量不断升高,退化为沙地时,土壤粘粒、粉砂粒含量合计不足10%,沙粒含量高达90%以上;土壤的持水和保水能力下降,土壤含水量呈降低的趋势,沙化地土壤0 cm～10 cm含水量仅57.88 g.kg-1,不到湿地土壤含水量的1/10,仅为草地土壤含水量的1/7。

Investigation and soil sampling analysis were made of degraded wetland and deserted grassland in Zoigê.The results were as follows：the content of organic matter,total N,P and available N,P,K in soil significantly reduced in the process of Zoigê wetland degradation and grassland desertification;and the content of clay and powder sand in soil continuously declined and the sand content increased;the content of clay and powder sand was less than 10% and the sand content reached more than 90% in deserted grassland;and the water retention ability of soil dropped,the soil moisture reduced.The moisture in the soil of 0 cm^10 cm depth was only 57.88 g·kg-1 in deserted grassland,less than 1/10 of soil moisture in the wetland,and only 1/7 of the soil moisture in the grassland,respectively.